Copper-amine complex solution as a low-emission catalyst for flexible polyurethane foam preparation

Abstract

A low-emission catalyst for the preparation of flexible polyurethane (FPUR) foams was developed. Copper-amine complex solutions in ethylene glycol (EG), namely, Cu(OAc)2(en)2-EG and Cu(OAc)2(trien)-EG (en, ethylenediamine; trien, triethylenetetramine), were synthesized and used as catalysts for the preparation of FPUR foams. The synthesis of Cu(OAc)2(en)2-EG and Cu(OAc)2(trien)-EG is convenient because the synthesis of copper-amine complexes can be done in situ using ethylene glycol as a solvent and no purification step is needed. It was found that Cu(OAc)2(en)2-EG was a suitable catalyst for FPUR foam preparation. In comparison to Dabco EG (or triethylenediamine), which is a commercial catalyst for FPUR foam preparation, Cu(OAc)2(en)2-EG had a comparable catalytic activity in gelling reaction and a higher catalytic activity in blowing reaction. The FPUR foam prepared from Cu(OAc)2(en)2-EG had a lower density than that prepared from Dabco EG.